Field of the Invention
The present invention relates to an apparatus used to control operations of a plurality of stepper motors in an apparatus such as a printing apparatus using a plurality of the stepper motors. Generally, a stepper motor is widely used for a speed control, a positioning control or the like on a printing paper conveying system, an operating unit or the like as a controlling actuator in a printing apparatus, for example, since the stepper motor is controllable by a digital signal, capable of controlling a speed in a wide range, capable of a highly accurate positioning, and capable of freely changing the rotating direction, etc. The stepper motor is rotated by switching a phase according to a pulse signal (stepper motor driving phase signal). By changing the stepper motor driving phase signal, it is possible to obtain a desired rotation speed.
In a stepper motor controlling apparatus, driving data (hereinafter referred to as sluing data) for creating the above stepper motor driving phase signal is beforehand prepared for each stepper motor.
When it is desired to rotate the stepper motor at a specific rotation speed, for example, sluing data for acceleration or deceleration until the stepper motor reaches a target rotation speed is required. In order to rotate the stepper motor at a constant speed after the stepper motor reaches the target rotation speed, sluing data for a constant speed is required. These sluing data are prepared for each stepper motor.
In, for example, a printing apparatus or the like, various sluing data is beforehand prepared for each stepper motor, the sluing data is stored in a storage medium such as a ROM or the like, required sluing data among these sluing data stored in the storage medium is read out according a program beforehand prepared under a control of a CPU (Central Processing Unit) or the like, and the stepper motor is driven by driving data created from the sluing data.
In the above stepper motor controlling apparatus, all sluing data is prepared for each stepper motor. In an apparatus including a plurality of stepper motors, for example, it is necessary to provide a region for storing sluing data for all the stepper motors in a storage medium such as a memory or the like. For this, the region in which sluing data is stored is increased with increasing the number of used stepper motors, hence a required capacity of the storage medium is increased.
Since a stepper motor is generally at a lower cost than a DC motor, there is an economical demand to use a stepper motor in a position where a motor is used as far as possible in designing an apparatus, so that the number of used stepper motors is inevitably increased, which leads to an increase of a capacity of the storage medium required to store the sluing data.
An object of the present invention is to provide a stepper motor controlling apparatus in which a capacity of a storing unit required for driving data is decreased by decreasing a quantity of the driving data.
The present invention therefore provides a stepper motor controlling apparatus having a plurality of controlling circuits controlling operations of a plurality of stepper motors, respectively, comprising a storing unit for storing driving data for generating a stepper motor driving phase signal in each of the controlling circuits, wherein the plural controlling circuits share the driving data in the storing unit.
According to the stepper motor controlling apparatus of this invention, driving data for creating a stepper motor driving phase signal in each of the controlling circuits is stored in the storing unit, and the plural controlling circuits share the driving data in the storing unit, so that it is unnecessary to store duplicate driving data in the storing unit. In consequence, this leads to a saving of a capacity of the storing unit, and it is economical.